docs: def _is_allowed_abbr(self, tokens):
          """Return True if text is an allowed abbreviation."""
          if len(tokens) <= 2:
              abbr_text = ''.join(tokens)
              if self.abbr_min <= len(abbr_text) <= self.abbr_max and bracket_level(abbr_text) == 0:
                  if abbr_text[0].isalnum() and any(c.isalpha() for c in abbr_text):
                      # Disallow property values
                      if re.match('^\d+(\.\d+)?(g|m[lL]|cm)$', abbr_text):
                          return False
                      return True
          return False